March 24, 2017

Not all spiral galaxies have to be picture-perfect to be striking. Messier 96, also known as NGC 3368, is a case in point: its core is displaced from the centre, its gas and dust are distributed asymmetrically and its spiral arms are ill-defined. But this portrait, taken with the FORS1 instrument on ESO’s Very Large Telescope, shows that imperfection is beauty in Messier 96. The galaxy's core is compact but glowing, and the dark dust lanes around it move in a delicate swirl towards the nucleus. And the spiral arms, patchy rings of young blue stars, are like necklaces of blue pearls.

Messier 96 lies in the constellation of Leo (The Lion). It is the largest galaxy in the Leo I group of galaxies; including its outermost spiral arms, it spans some 100 000 light-years in diameter — about the size of our Milky Way. Its graceful imperfections likely result from the gravitational pull of other members in the group, or are perhaps due to past galactic encounters.

A multitude of background galaxies peers through the dusty spiral. Perhaps the most striking of these objects is an edge-on galaxy that — because of a chance alignment — appears to interrupt the outermost spiral arm to the upper left of Messier 96's core.

The image was made with data taken at visible and infrared wavelengths through B, V, and I filters.

The galaxy 3C186, located about 8 billion years from Earth, is most likely the result of a merger of two galaxies. This is supported by arc-shaped tidal tails, usually produced by a gravitational tug between two colliding galaxies, identified by the scientists. The merger of the galaxies also led to a merger of the two supermassive black holes in their centres, and the resultant black hole was then kicked out of its parent galaxy by the gravitational waves created by the merger.

The bright, star-like looking quasar can be seen in the centre of the image. Its former host galaxy is the faint, extended object behind it.

An international team of astronomers using the NASA/ESA Hubble Space Telescope have uncovered a supermassive black hole that has been propelled out of the centre of the distant galaxy 3C186. The black hole was most likely ejected by the power of gravitational waves. This is the first time that astronomers found a supermassive black hole at such a large distance from its host galaxy centre.

Though several other suspected runaway black holes have been seen elsewhere, none has so far been confirmed. Now astronomers using the NASA/ESA Hubble Space Telescope have detected a supermassive black hole, with a mass of one billion times the Sun’s, being kicked out of its parent galaxy. “We estimate that it took the equivalent energy of 100 million supernovae exploding simultaneously to jettison the black hole,” describes Stefano Bianchi, co-author of the study, from the Roma Tre University, Italy.

The images taken by Hubble provided the first clue that the galaxy, named 3C186, was unusual. The images of the galaxy, located 8 billion light-years away, revealed a bright quasar, the energetic signature of an active black hole, located far from the galactic core. “Black holes reside in the centres of galaxies, so it’s unusual to see a quasar not in the centre,” recalls team leader Marco Chiaberge, ESA-AURA researcher at the Space Telescope Science Institute, USA.

The team calculated that the black hole has already travelled about 35 000 light-years from the centre, which is more than the distance between the Sun and the centre of the Milky Way. And it continues its flight at a speed of 7.5 million kilometres per hour. At this speed the black hole could travel from Earth to the Moon in three minutes.

Although other scenarios to explain the observations cannot be excluded, the most plausible source of the propulsive energy is that this supermassive black hole was given a kick by gravitational waves unleashed by the merger of two massive black holes at the centre of its host galaxy. This theory is supported by arc-shaped tidal tails identified by the scientists, produced by a gravitational tug between two colliding galaxies.

According to the theory presented by the scientists, 1-2 billion years ago two galaxies — each with central, massive black holes — merged. The black holes whirled around each other at the centre of the newly-formed elliptical galaxy, creating gravitational waves that were flung out like water from a lawn sprinkler. As the two black holes did not have the same mass and rotation rate, they emitted gravitational waves more strongly along one direction. When the two black holes finally merged, the anisotropic emission of gravitational waves generated a kick that shot the resulting black hole out of the galactic centre.

“If our theory is correct, the observations provide strong evidence that supermassive black holes can actually merge,” explains Stefano Bianchi on the importance of the discovery. “There is already evidence of black hole collisions for stellar-mass black holes, but the process regulating supermassive black holes is more complex and not yet completely understood.”

The researchers are lucky to have caught this unique event because not every black hole merger produces imbalanced gravitational waves that propel a black hole out of the galaxy. The team now wants to secure further observation time with Hubble, in combination with the Atacama Large Millimeter/submillimeter Array (ALMA) and other facilities, to more accurately measure the speed of the black hole and its surrounding gas disc, which may yield further insights into the nature of this rare object.

The Sun has been virtually spotless, as in no sunspots, over the past 11 days, a spotless stretch that we have not seen since the last solar minimum many years ago. The videos shows the past four days (March 14-17, 2017) with a combination of an extreme ultraviolet image blended with just the filtered Sun. If we just showed the filtered Sun with no spots for reference points, any viewer would have a hard time telling that the Sun was even rotating. The Sun is trending again towards the solar minimum period of its 11 year cycle, which is predicted to be around 2020.

This image, taken with the NASA/ESA Hubble Space Telescope, shows the supernova remnant SNR 0509-68.7, also known as N103B. N103B was a Type Ia supernova, located in the Large Magellanic Cloud — a neighbouring galaxy of the Milky Way. Owing to its relative proximity to Earth, astronomers observe the remnant to search for a potential stellar survivor of the explosion. This could shed more light on the exact mechanism behind type Ia supernovae.

The actual supernova remnant is the irregular shaped dust cloud, close to the centre of the image.

The gas in the lower half of the image and the dense concentration of stars in the lower left are the outskirts of the star cluster NGC 1850, which has been observed by Hubble in the past.

March 22, 2017

Adansonia grandidieri, sometimes known as Grandidier's baobab, is the biggest and most famous of Madagascar's six species of baobabs. This imposing and unusual tree is endemic to the island of Madagascar, where it is an endangered species threatened by the encroachment of agricultural land.

Grandidier's baobabs have massive cylindrical trunks, up to three meters across, covered with smooth, reddish-grey bark. They can reach 25 to 30 m (82 to 98 ft) in height. At certain times of the year the flat-topped crowns bear bluish-green palmate leaves, dark brown floral buds or spectacular flowers with white petals. The large, dry fruits of the baobab contain kidney-shaped seeds within an edible pulp.

This baobab occurs in south-western Madagascar between Lac Ihotry (near Morombe) and Bereboka. Grandidier's baobab used to inhabit dry, deciduous forest, especially near seasonal rivers or lakes. However, today it is mainly found in open, agricultural land or degraded scrubland.

The long-lived Grandidier's baobab is in leaf from October to May, and flowers between May and August. The flowers, said to smell of sour watermelon, open just before or soon after dusk, and all the pollen is released during the first night. The tree is pollinated by nocturnal mammals, such as fork-marked lemurs and insects like the Hawk Moth. The lemurs move through the canopies, inserting their snouts into the white flowers and licking nectar from the petal bases, resulting in pollen being deposited in the lemurs' faces, whereas the moth is slightly more effective at pollination because it is able to fly from tree to tree with most of its body covered in pollen.

The species bears ripe fruit in November and December. Unlike the baobabs of Africa and Australia, it appears that the seeds of the tasty fruit are not dispersed by animals. Lemurs are the only living animals on Madagascar that are capable of acting as seed dispersers, yet seed dispersal by lemurs has never been documented. In the past, however, this could have been very different. There are several species that have gone extinct since human colonization of the island (1,500 to 2,000 years ago) that could very likely have been dispersers of the seeds. This includes species of primates that were thought to be similar to baboons, and the heaviest bird that ever lived, the elephant bird, which had a powerful beak that could have opened large fruit. Today, water may be the means by which the seeds are dispersed.

Lack of water can sometimes be a problem for plants in Madagascar. It appears that the baobab overcomes this by storing water within the fibrous wood of the trunk, as the tree's diameter fluctuates with rainfall.

This animation shows how the illumination of Ceres' northern hemisphere varies with the dwarf planet's axial tilt, or obliquity.

In the first frame the northern hemisphere is shown when Ceres' obliquity is 2 degrees, which is the minimum tilt. Regions that remain in shadow are shown in blue. The illumination shown is for the northern solstice, which is when the north pole is most illuminated.

The second frame shows the same scene when Ceres' obliquity is 12 degrees. More polar regions are illuminated (this view is also for the northern solstice). The area of the regions that remain in shadow, marked with blue dots, is much smaller.

The third frame shows the same scene when Ceres' obliquity is 20 degrees, which is the maximum tilt. The red circles show the only two craters in this scene that still have permanently shadowed regions. The polar regions are much better illuminated at this high obliquity.

New NASA research reveals that the giant Martian shield volcano Arsia Mons produced one new lava flow at its summit every 1 to 3 million years during the final peak of activity. The last volcanic activity there ceased about 50 million years ago—around the time of Earth’s Cretaceous–Paleogene extinction, when large numbers of our planet’s plant and animal species (including dinosaurs) went extinct.

Located just south of Mars’ equator, Arsia Mons is the southernmost member of a trio of broad, gently sloping shield volcanoes collectively known as Tharsis Montes. Arsia Mons was built up over billions of years, though the details of its lifecycle are still being worked out. The most recent volcanic activity is thought to have taken place in the caldera—the bowl-shaped depression at the top—where 29 volcanic vents have been identified. Until now, it’s been difficult to make a precise estimate of when this volcanic field was active.

“We estimate that the peak activity for the volcanic field at the summit of Arsia Mons probably occurred approximately 150 million years ago—the late Jurassic period on Earth—and then died out around the same time as Earth’s dinosaurs,” said Jacob Richardson, a postdoctoral researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s possible, though, that the last volcanic vent or two might have been active in the past 50 million years, which is very recent in geological terms.”

Measuring about 68 miles (110 kilometers) across, the caldera is deep enough to hold the entire volume of water in Lake Huron, and then some. Examining the volcanic features within the caldera required high-resolution imaging, which the researchers obtained from the Context Camera on NASA’s Mars Reconnaissance Orbiter.

The team mapped the boundaries of the lava flows from each of the 29 volcanic vents and determined the stratigraphy, or layering, of the flows. The researchers also performed a technique called crater counting—tallying up the number of craters at least 330 feet (100 meters) in diameter—to estimate the ages of the flows.

Using a new computer model developed by Richardson and his colleagues at the University of South Florida, the two types of information were combined to determine the volcanic equivalent of a batting lineup for Arsia Mons’ 29 vents. The oldest flows date back about 200 million years. The youngest flows probably occurred 10 to 90 million years ago—most likely around 50 million years ago.

The modeling also yielded estimates of the volume flux for each lava flow. At their peak about 150 million years ago, the vents in the Arsia Mons’ caldera probably collectively produced about 1 to 8 cubic kilometers of magma every million years, slowly adding to the volcano’s size.

“Think of it like a slow, leaky faucet of magma,” said Richardson. “Arsia Mons was creating about one volcanic vent every 1 to 3 million years at the peak, compared to one every 10,000 years or so in similar regions on Earth.”

A better understanding of when volcanic activity on Mars took place is important because it helps researchers understand the Red Planet’s history and interior structure.

“A major goal of the Mars volcanology community is to understand the anatomy and lifecycle of the planet’s volcanoes. Mars’ volcanoes show evidence for activity over a larger time span than those on Earth, but their histories of magma production might be quite different,” said Jacob Bleacher, a planetary geologist at Goddard and a co-author on the study. “This study gives us another clue about how activity at Arsia Mons tailed off and the huge volcano became quiet.”

March 21, 2017

Some galaxies are harder to classify than others. Here, Hubble’s trusty Wide Field Camera 3 (WFC3) has captured a striking view of two interacting galaxies located some 60 million light-years away in the constellation of Leo (The Lion). The more diffuse and patchy blue glow covering the right side of the frame is known as NGC 3447 — sometimes NGC 3447B for clarity, as the name NGC 3447 can apply to the overall duo. The smaller clump to the upper left is known as NGC 3447A.

The trouble with space is that it is, to state the obvious, really, really big. Astronomers have for hundreds of years been discovering and naming galaxies, stars, cosmic clouds and more. Unifying and regulating the conventions and classifications for everything ever observed is very difficult, especially when you get an ambiguous object like NGC 3447, which stubbornly defies easy categorisation.

Overall, we know NGC 3447 comprises a couple of interacting galaxies, but we’re unsure what each looked like before they began to tear one another apart. The two sit so close that they are strongly influenced and distorted by the gravitational forces between them, causing the galaxies to twist themselves into the unusual and unique shapes seen here. NGC 3447A appears to display the remnants of a central bar structure and some disrupted spiral arms, both properties characteristic of certain spiral galaxies. Some identify NGC 3447B as a former spiral galaxy, while others categorise it as being an irregular galaxy.

This image, taken by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, shows glowing dust inside the protocluster NGC 6334I. Studying this star-forming cloud in the Cat’s Paw Nebula (NGC 6334) with both ALMA and the Submillimeter Array (SMA) in Hawaii astronomers could see that something dramatic had taken place, completely changing a stellar nursery over a surprisingly short period of time.

It is known that young stars form inside protoclusters when pockets of gas become so dense that they begin to collapse under their own gravity. Over time, discs of dust and gas form around these nascent stars and funnel material onto their surfaces helping them grow.

However, this new image from ALMA shows a massive protostar, nestled deep within this dust-filled stellar nursery, that is undergoing an intense growth spurt, most likely triggered by an avalanche of gas falling onto its surface. This new material feeding it is causing the protostar to shine nearly 100 times brighter than before.The discovery of this outburst supports the theory that young stars can undergo intense growth spurts that reshape their surroundings.

This artist’s rendering shows the tidal disruption event named ASASSN-14li, where a star wandering too close to a 3-million-solar-mass black hole was torn apart. The debris gathered into an accretion disk around the black hole. New data from NASA's Swift satellite show that the initial formation of the disk was shaped by interactions among incoming and outgoing streams of tidal debris.

Some 290 million years ago, a star much like the sun wandered too close to the central black hole of its galaxy. Intense tides tore the star apart, which produced an eruption of optical, ultraviolet and X-ray light that first reached Earth in 2014. Now, a team of scientists using observations from NASA's Swift satellite have mapped out how and where these different wavelengths were produced in the event, named ASASSN-14li, as the shattered star's debris circled the black hole.

"We discovered brightness changes in X-rays that occurred about a month after similar changes were observed in visible and UV light," said Dheeraj Pasham, an astrophysicist at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts, and the lead researcher of the study. "We think this means the optical and UV emission arose far from the black hole, where elliptical streams of orbiting matter crashed into each other."

Astronomers think ASASSN-14li was produced when a sun-like star wandered too close to a 3-million-solar-mass black hole similar to the one at the center of our own galaxy. For comparison, the event horizon of a black hole like this is about 13 times bigger than the sun, and the accretion disk formed by the disrupted star could extend to more than twice Earth's distance from the sun.

When a star passes too close to a black hole with 10,000 or more times the sun's mass, tidal forces outstrip the star's own gravity, converting the star into a stream of debris. Astronomers call this a tidal disruption event. Matter falling toward a black hole collects into a spinning accretion disk, where it becomes compressed and heated before eventually spilling over the black hole's event horizon, the point beyond which nothing can escape and astronomers cannot observe. Tidal disruption flares carry important information about how this debris initially settles into an accretion disk.

Astronomers know the X-ray emission in these flares arises very close to the black hole. But the location of optical and UV light was unclear, even puzzling. In some of the best-studied events, this emission seems to be located much farther than where the black hole's tides could shatter the star. Additionally, the gas emitting the light seemed to remain at steady temperatures for much longer than expected.

ASASSN-14li was discovered November 22, 2014, in images obtained by the All Sky Automated Survey for SuperNovae (ASASSN), which includes robotic telescopes in Hawaii and Chile. Follow-up observations with Swift's X-ray and Ultraviolet/Optical telescopes began eight days later and continued every few days for the next nine months. The researchers supplemented later Swift observations with optical data from the Las Cumbres Observatory headquartered in Goleta, California.

The results show how interactions among the infalling debris could create the observed optical and UV emission.

Tidal debris initially falls toward the black hole but overshoots, arcing back out along elliptical orbits and eventually colliding with the incoming stream.

"Returning clumps of debris strike the incoming stream, which results in shock waves that emit visible and ultraviolet light," said Goddard's Bradley Cenko, the acting Swift principal investigator and a member of the science team. "As these clumps fall down to the black hole, they also modulate the X-ray emission there."

Future observations of other tidal disruption events will be needed to further clarify the origin of optical and ultraviolet light.

March 20, 2017

This image shows the swirling shape of galaxy NGC 2217, in the constellation of Canis Major (The Great Dog). In the central region of the galaxy is a distinctive bar of stars within an oval ring. Further out, a set of tightly wound spiral arms almost form a circular ring around the galaxy. NGC 2217 is therefore classified as a barred spiral galaxy, and its circular appearance indicates that we see it nearly face-on.

The outer spiral arms have a bluish colour, indicating the presence of hot, luminous, young stars, born out of clouds of interstellar gas. The central bulge and bar are yellower in appearance, due to the presence of older stars. Dark streaks can also be seen in places against the galaxy’s arms and central bulge, where lanes of cosmic dust block out some of the starlight.

The majority of spiral galaxies in the local Universe — including our own Milky Way — are thought to have a bar of some kind, and these structures play an important role in the development of a galaxy. They can, for example, funnel gas towards the centre of the galaxy, helping to feed a central black hole, or to form new stars.

Dracaena cinnabari, the Socotra dragon tree or dragon blood tree, is a dragon tree native to the Socotra archipelago, part of Yemen, located in the Arabian Sea. It is so called due to the red sap that the trees produce.

The dragon blood tree has a unique and strange appearance, with an "upturned, densely packed crown having the shape of an uprightly held umbrella". This evergreen species is named after its dark red resin, which is known as "dragon's blood". Unlike most monocot plants, Dracaena displays secondary growth, D. cinnabari even has growth zones resembling tree rings found in dicot tree species. Along with other arborescent Dracaena species it has a distinctive growth habit called "dracoid habitus". Its leaves are found only at the end of its youngest branches; its leaves are all shed every 3 or 4 years before new leaves simultaneously mature. Branching tends to occur when the growth of the terminal bud is stopped, due to either flowering or traumatic events (e.g. herbivory).

Its fruits are small fleshy berries containing between 1 and 3 seeds. As they develop they turn from green to black, and then become orange when ripe. The berries are eaten by birds (e.g. Onychognatus species) and thereby dispersed. The seeds are 4–5 mm in diameter and weigh on average 68 mg. The berries exude a deep red resin, known as dragon’s blood.

Like other monocotyledons, such as palms, the dragon’s blood tree grows from the tip of the stem, with the long, stiff leaves borne in dense rosettes at the end (4, 5, 7). It branches at maturity to produce an umbrella-shaped crown, with leaves that measure up to 60 cm long and 3 cm wide. The trunk and the branches of the dragon blood are thick and stout and display dichotomous branching, where each of the branches repeatedly divides in two sections.

The dragon's blood tree usually produces its flowers around February, though flowering does vary with location. The flowers tend to grow at the end of the branches. The flowers have inflorescences, and they bear small clusters of fragrant, white or green flowers. The fruits take five months to completely mature. The fruits are described as a fleshy berry, which changes from green to black as it gradually ripens. The fleshy berry fruit ends up being an orange-red color that contains one to three seeds. The berries are usually eaten and dispersed by birds and other animals.

The unusual shape of the dragon's blood tree is an adaptation for survival in arid conditions with low amounts of soil, such as in mountaintops. The large, packed crown provides shade and reduces evaporation. This shade also aids in the survival of seedlings growing beneath the adult tree, explaining why the trees tend to grow closer together.

March 19, 2017

Resembling a diamond-encrusted bracelet, a ring of brilliant blue star clusters wraps around the yellowish nucleus of what was once a normal spiral galaxy in this new image from the NASA/ESA Hubble Space Telescope (HST). This image is being released to commemorate the 14th anniversary of Hubble's launch on April 24, 1990 and its deployment from the space shuttle Discovery on April 25, 1990.

The sparkling blue ring is 150,000 light-years in diameter, making it larger than our entire home galaxy, the Milky Way. The galaxy, cataloged as AM 0644-741, is a member of the class of so- called "ring galaxies." It lies 300 million light-years away in the direction of the southern constellation Dorado.

Jasper National Park is the largest national park in the Canadian Rockies, spanning 10,878 km2 (4,200 sq mi). It is located in the province of Alberta, north of Banff National Park and west of Edmonton. The park includes the glaciers of the Columbia Icefield, hot springs, lakes, waterfalls and mountains.

Jasper was named after Jasper Hawes, who operated a trading post in the region for the North West Company. Before this it was referred to as Fitzhugh. The park was established on September 14, 1907 as Jasper Forest Park, and was granted national park status in 1930, with the passing of the National Parks Act. In 2014, Jasper National Park had 2,154,710 visitors.

Mammalian species found in the park are the elk, caribou ( also known as Reindeer,) moose, mule deer, white-tailed deer, porcupine, lynx, beaver, two species of fox, marten, pika, grizzly bear, coyote, mountain goat, bighorn sheep, black bear, timber wolf, hoary marmot, cougar, and wolverine. The most common birds that fly around this park including raptors are bald eagles, golden eagles, Great horned owls, spruce grouses, white-tailed ptarmigans, bohemian waxwings, and evening grosbeaks. Canada geese and red-necked grebes mostly float on Maligne Lake.

The park was declared a UNESCO World Heritage Site in 1984, together with the other national and provincial parks that form the Canadian Rocky Mountain Parks, for the mountain landscapes containing mountain peaks, glaciers, lakes, waterfalls, canyons, and limestone caves as well as fossils found here.

Major river systems originating in the park include the Athabasca and Smoky rivers (part of the Arctic Ocean basin).

Some of the park's scenic attractions include Mount Edith Cavell, Pyramid Lake with Pyramid Mountain, Maligne Lake, Medicine Lake, and the Tonquin Valley. Other attractions are the Marmot Basin ski area; the Snocoach tours of the Athabasca Glacier, an outlet glacier of the Columbia Icefield; Athabasca Falls; the Jasper Skytram, and numerous other outdoor related recreational activities (such as hiking, fishing, wildlife viewing, rafting, kayaking and camping). The Miette Hot Springs are located close to the northeast entrance. The Miette Hot Springs are created by an extremely hot spring cooled by the mountain to temperatures suitable for humans.

The Icefields Parkway is a highway 230 km (140 mi) in length from Lake Louise, Alberta in Banff National Park, to Jasper, Alberta. The highway parallels the continental divide, providing motor and cycle access to the mountains. The Athabasca and Sunwapta Falls are both accessible by the road.